Zach Ward

-2004 Silverado 1500 5.3L
My instrument cluster was acting up for a week or so and it was saying that my battery wasnt charging. I didnt pay attention to it due to the instrument cluster being out of wack. After dying on the road and replacing the alternator and battery my idle was almost half it was previous to alternator swap. My question is what could lead to a lower idle speed whether it be sensors or a more mechanical issue? My usual rpm in park and drive with the brakes on was about 1100. After the swap its down to 600 in park and 500 in drive with the brakes on. Any help would be appreciated

mountainmanjoe

The computer may have lost its idle calibration when you swapped the battery. If you drive it a bit more, it may adjust itself.

1100 sounds too high to me. I thought it should be around 700 idling in park. It might have been higher before because the battery was loading down the electrical system, and the computer was trying to compensate.

Zach Ward

Alright thanks I will look into that idle relearn and hope that fixes the problem